TeamSwift

Home of the Suzuki mini-compacts ! Your Home for all things Suzuki Swift, Geo Metro, Holden Barina, Chevy Sprint, Pontiac Firefly, and Suzuki Cultus. TeamSwift is a technical performance oriented community!
It is currently Thu Oct 19, 2017 10:52 pm

Underbody braces, turbos and more!

All times are UTC - 5 hours




Post new topic Reply to topic  [ 19 posts ] 
Author Message
PostPosted: Tue Sep 20, 2005 6:44 pm 
Offline

Joined: Tue Sep 20, 2005 6:20 pm
Posts: 8
Location: State College
I havent seen anyone say anything about this, but was wondering... Has anyone tried mounting some aluminum panels under their car to try to clean up the areodynamics? I have just started toying with the idea and am gonna try finding a source for some thin gauge and mount under my car to give it a try. Any thoughts? Thanx.

[MOD EDIT] updated title


Top
 Profile  
 
 Post subject:
PostPosted: Tue Sep 20, 2005 9:46 pm 
Offline

Joined: Mon Jun 06, 2005 8:19 pm
Posts: 274
Location: Vancouver
I've thought about it too, doesn't Lexus do something like that to their cars? Let us know how it goes. Maybe smaller mirrors and different front bumper might be easier and net similar results?


Top
 Profile  
 
 Post subject:
PostPosted: Tue Sep 20, 2005 9:48 pm 
Offline

Joined: Sat Jan 24, 2004 5:15 pm
Posts: 391
Location: Altamonte Springs, FL
Tin/sheetmetal (comes in 12" ~ maybe 24/36" widths on a roll)?
Thicker?
Aluminium sheeting?

Hmm, methods of attachment:
Rivnuts (rivets with threaded nuts on the end, needs a "rivnut" gun..)
generic sheetmetal screws?
Some 90* angle screwed on here/there?

:?:

_________________
<img src="http://tellico.off-road.com/wwwthreads_uploads/1438321-lolsroyce.gif">


Top
 Profile  
 
 Post subject:
PostPosted: Tue Sep 20, 2005 9:52 pm 
Offline

Joined: Sat Jan 24, 2004 5:15 pm
Posts: 391
Location: Altamonte Springs, FL
Seems with one of these
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=34104
You could make runners/dimples (whatever the "DENTS" are called in sheetmetal to give support/rigidity) or 90* bends to tuck up and under stuff.

_________________
<img src="http://tellico.off-road.com/wwwthreads_uploads/1438321-lolsroyce.gif">


Top
 Profile  
 
 Post subject:
PostPosted: Tue Sep 20, 2005 10:57 pm 
Offline
Former TeamSwift Admin
Former TeamSwift Admin
User avatar

Joined: Tue Nov 19, 2002 9:58 am
Posts: 8146
Location: Seattle, WA
the newer porsches all have covers that go under the engine bay to create a smooth bottom to the entire car (including the transmission tunnel), it definately works, BUT you'll probably see higher oil & water temps as you're restricting airflow in the engine compartment. rally suzuki said he had to install an oil cooler after fitting a skid plate just from the reduced airflow around the oil pan.
you'd probably find it more useful to first lower the car and install a LOW front air dam and side skirts. if you're on a budget, lawn edging from home depot works great.
eg.
Valley View
Professional Edging, 20 Ft.
Model PRO-20
Image

_________________
'92 Swift GT, '94 Swift GT, '88 Turbo Sprint, '98 Swift ... all sold years ago


Top
 Profile  
 
 Post subject:
PostPosted: Wed Sep 28, 2005 1:59 am 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
that's funny - i did the lawn edging dam/skirts thing to a rabbit i owned years ago. never could tell if it worked...

maybe that's because it didn't make an easily measurable difference.

if you're interested in some numbers for this sort of thing, honda measured the difference from adding more aerodynamic wheels and a decklid spoiler to their accord hybrid, compared to the non-hybrid car. these changes improved the coefficient of drag from .30 to .29

overall, the hybrid gets 7 mpg (US) better economy on the hwy than the non-hybrid.

the engineers attribute 5% of this 7 mpg improvement to the aerodynamic changes. 5% of 7 mpg is around 1/3 mpg US. (.35 mpg)

http://www.hondanews.com/CatID2131?mid=2004091746959&mime=asc

does this mean aerodynamic changes aren't worth the effort?

maybe not. they didn't try nearly as hard on the accord hybrid as they did with the insight, which has much more aerodynamic wheels, skirts on the rear wheel openings, and added underbody panels. it's claimed the insight is the most aerodynamic mass-produced car at the moment.

http://www.insightcentral.net/encyclopedia/enaero.html

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Top
 Profile  
 
 Post subject:
PostPosted: Wed Sep 28, 2005 8:15 am 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
okay, couldn't sleep last night.

so i did a bit more reading on honda's site about the aerodynamics of the insight.

they say the flat underbody <a href="http://www.hondanews.com/CatID2055?mid=20010221001329&mime=asc"><b>greatly</b> contributes to the Insight body's low coefficient of drag</a>.

(my emphasis)

too bad they don't define "greatly" in numbers like they did with the changes to the accord.

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Top
 Profile  
 
 Post subject:
PostPosted: Wed Sep 28, 2005 10:42 am 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
ok, i really should be working.

i've "insighted" a metro in photoshop.

and i confidently predict (based on no hard evidence whatsoever) that the following aero mods will return at least a 4% improvement in highway fuel economy:

as shown (or not) in the "photo" below:

- car lowered 2.5 inches
- 2 inch front air dam and rocker panel skirts (lawn edging!)
- 3 inch dams ahead of each tire
- flat disc-style wheels/wheel covers
- rear wheel skirts
- underbody flat panels
- dual windshield wipers converted to single wiper, centrally mounted and parked vertically (argue about safety here)

and now back to work...

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Top
 Profile  
 
 Post subject:
PostPosted: Wed Sep 28, 2005 10:46 am 
Offline

Joined: Thu Jul 01, 2004 3:52 am
Posts: 1540
Location: Vancouver, BC, Canada
good luck on your research.

let us know if it imrpove mpg very greatly.

_________________
sorry bout my bad english


Top
 Profile  
 
 Post subject:
PostPosted: Wed Sep 28, 2005 10:48 am 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
oh, i don't think i'm going to do all this!

i was just brainstorming.

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Top
 Profile  
 
 Post subject:
PostPosted: Thu Sep 29, 2005 8:01 am 
Offline
Moderator & FAQ King
Moderator & FAQ King
User avatar

Joined: Wed Apr 09, 2003 6:22 pm
Posts: 6460
Location: Vancouver, BC
More ideas:
• replace side mirrors with something smaller (perhaps video cameras?)
• shave unneccesary protrusions (washer jets, radio antenna, door handles)
• smooth over unneccesary gaps (cowl vent, panel gaps)
• use NACA ducts where you need air inlets (instead of opening the window)
• chop out the overhang on the rear bumper (transition it to the undertray)
• do as Metropwr did, and fill in the extra holes in the front bumper
• ovalized tubular control arms

_________________
jaguar,vettes&sprints wrote:
...can you inlighten me about lihtan's
( miracle pour hole)
maybe a picture Thanks


Top
 Profile  
 
 Post subject:
PostPosted: Thu Sep 29, 2005 8:56 am 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
here's a link to a guy who added a wing to a vw beetle and claims improved mileage of 5-8%

<a href="http://www.max-mpg.com/html/tech/main.htm">http://www.max-mpg.com/html/tech/main.htm</a>

then again, he points out the beetle is a fairly un-aerodynamic car to begin with.

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Top
 Profile  
 
 Post subject:
PostPosted: Thu Sep 29, 2005 10:03 am 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
okay, so we've got lots of aero mod ideas, some easy, some uh, more challenging

the question is how to test these to find out if they work, without the benefit of a wind tunnel

i suppose you could make some mods and just watch fuel ecomony at subsequent fill-ups, but there are so many other variables in the time/distance to go through a tank of gas, the results will be masked/affected by other factors

we need more 'instant' readings.

one idea i had is a "coast down" test. e.g. drive at a steady 120 km/h on a deserted road and depress the clutch at a known point on the roadway. then record the spot where the car rolls to a stop. make aero modifications, repeat, record, etc.

do runs in both directions to average out grade & wind.

or use a stopwatch to measure the time it takes to coast down from 120 to, say 50 (i have read that aerodynamics come in to play around 50 km/h, so coasting below that may not tell you much).

this way you could test mods before investing a lot of effort in them (e.g. duct tape and cardboard underbody panels/wheel skirts before fabricating metal ones).

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Top
 Profile  
 
 Post subject:
PostPosted: Thu Sep 29, 2005 11:16 pm 
Offline
User avatar

Joined: Mon Mar 21, 2005 4:52 pm
Posts: 634
Location: Eastern Ontario
link to an article about a guy who seriously aero-modded his toyota tacoma pickup truck and improved his hwy mileage by 28%

<a href="http://www.evworld.com/view.cfm?section=article&storyid=870">http://www.evworld.com/view.cfm?section=article&storyid=870</a>

_________________
Image
www.MetroMPG.com ... www.ForkenSwift.com
... www.EcoModder.com


Last edited by geometro on Thu Dec 01, 2005 11:28 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Fri Sep 30, 2005 10:59 am 
Offline
Moderator & FAQ King
Moderator & FAQ King
User avatar

Joined: Wed Apr 09, 2003 6:22 pm
Posts: 6460
Location: Vancouver, BC
I read the whole Toyota article include all the comments. And it really got me thinking. I had no idea that aerodynamics would be such a major contributor to improving the vehicle's efficiency (although with a brick of a truck anything would help).

About wind tunnel testing: aerodynamic properties are the same at any scale. An accurate miniature model of your car would test the same as the full size version. There's no reason you can't do testing with a home brew mini air tunnel or water tank. You can also do live aerodynamic studies right on your own vehicle using yarn and tape:

Aero Testing Part 1:
http://autospeed.drive.com.au/cms/A_1044/article.html

Aero Testing Part 2:
http://autospeed.drive.com.au/cms/A_1055/article.html

Aero Testing Part 3:
http://autospeed.drive.com.au/cms/A_1065/article.html

Aero Testing Part 4:
http://autospeed.drive.com.au/cms/A_1071/article.html

Aero Testing Part 5:
http://autospeed.drive.com.au/cms/A_1080/article.html

Modifiying Under-Car Airflow:
http://autospeed.drive.com.au/cms/A_2455/article.html

Silencing Wiper Wind Noise:
http://autospeed.drive.com.au/cms/A_2445/article.html

_________________
jaguar,vettes&sprints wrote:
...can you inlighten me about lihtan's
( miracle pour hole)
maybe a picture Thanks


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 01, 2005 10:26 pm 
Offline
Suzuki Elder
User avatar

Joined: Mon Dec 01, 2003 12:47 pm
Posts: 11669
Location: columbus, ohio
the single largest contributor to drag is frontal surface area. the suzuki variants have that pretty well knocked. the rear of the swift isn't bad either and the gt's little air spoiler works great. i added the mid wing to lizzie's gti and i think those make the rear even a bit more slippery.

i changed my verts' mirrors over to the swift flag style mirrors which are a little larger and not as swept as the us market metro mirrors. if you're going aero, try those out.

_________________
1991 Blue Geo Metro Convertible highly modified 1.0L Turbo3 5 spd. - 1991 Red Geo Metro Convertible customized with a Twincam 5 spd.

My Turbo3 Project
My Cardomain Page -Ol' Blue
My YouTube Channel
My Photo Gallery
SAAB Sonett II


Top
 Profile  
 
 Post subject:
PostPosted: Mon Oct 03, 2005 12:41 pm 
Offline

Joined: Fri Sep 17, 2004 5:41 pm
Posts: 89
Location: Irvine, Ca
How about that rear hatch though? Think it would smooth out air flow to tear drop out the back end. I have a '94, so the rear hatch is much more vertical, so in theory turbulent.

I just switched to 145/12" new tires from 155/12". Although the nominal numbers are similar, the real measurements show the 145 to be way narrower and significantly shorter (and handle way worse).

I never noticed how tall the Mk4s were until hearing you talk about a 2.5" drop. I don't think the Mk3s can do that and still be practical.

Any thoughts on how to make wheel skirts work?

Anyone want to get extreme and narrow the rear track and sheet metal like the insight (an excellent aero design).

If underbody sheet metaling causes overheating, that should be easily fixed with some engine bay exaust ducts.

I have a single big wiper operating from the driver's side that does an adequite job. Tucking it under a cowl would be good... Or, rig it to be quick release/install and just keep it inside until you need it (more practical here in Southern Cal).

I've always toyed with the idea of pin cameras in place of mirrors, but only as an unecessary luxury item to sell to the local yuppies. Weight increases for the supporting equipment could easily wash the advantage of loosing mirrors. Can you invert the mirror to the inside corner of the car? Would increase your blind spot, but should still give you visibility. Probably law problems with this though.

Jay W
505/287 Dakota


Top
 Profile  
 
 Post subject:
PostPosted: Mon Oct 03, 2005 8:14 pm 
Offline

Joined: Wed Mar 23, 2005 7:35 pm
Posts: 172
Location: Dalton, GA.
You can keep the regular mirrors, just do some shopping around for a set with slightly slimmer profile.

I had a '94. From what I remember, they are already quite slender and cut well in the wind.
The wheel well idea isn't too bad. However, you may also get the same effect from simply installing a set of full moon wheel covers.

do a google for Autoenhance racing discs. They are the only place that I have found on the net that offers 12" trim rings and 12" racing discs(fullmoons)

[The full moon idea is just a little bit more drastic than the "aerodynamic" wheels on the Insight]

One last thing, I don't think that they are available in a 12" but do a search for "low rolling resistance tires"


Top
 Profile  
 
 Post subject:
PostPosted: Mon Oct 03, 2005 8:17 pm 
Offline

Joined: Wed Mar 23, 2005 7:35 pm
Posts: 172
Location: Dalton, GA.
There is also a body kit set on Ebay occasionally that would add some ground effects and essentially give the same effect as lowering.

The price on the body kit is really nice.

The kit also fits the Subaru Justy. So, if you can't find it on Ebay, just lok around on the net.

Cheers,
Jonathan


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 19 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group